1. Field of Invention
The present invention relates to a method of manufacturing a semiconductor device. More particularly, the present invention relates to a method for forming a metallic capacitor.
2. Description of Related Art
Polysilicon material is often used to fabricate capacitors in the manufacturing of conventional semiconductor devices. Polysilicon material is quite often used in the production of capacitors in the analog region of an integrated circuit where a host of other signal-producing devices also needs to be produced. In general, two polysilicon layers are required to form a capacitor.
One problem facing the production of a polysilicon capacitor is that the capacitance of a capacitor may differ considerably from place to place, and it is very difficult to achieve high uniformity. Since stability of capacitor capacitance is very important, particularly in the analog portion of an integrated circuit, the polysilicon capacitor is not an ideal design. In addition, polysilicon capacitor process is quite sensitive to processing parameters and external conditions. Hence, the stability of a capacitor is compromised even further.
Another problem facing polysilicon capacitor production is that many steps are required to produce a polysilicon capacitor and the process involves the use of a sophisticated control mechanism. Operations such as heating, doping and integrating demand considerable processing care. Therefore, a polysilicon capacitor is more costly to produce than a metallic capacitor.